The Buck

I have moved my operation out to my parents' barn, deep in the rolling hills and spring fields of the heartland. Being out here puts me a minimum of five miles from the nearest hardware store, and twenty miles from any place which might carry a decent selection of materials. Still, it is the only place where I can get enough space to construct something so large. Also, I have been working for a while to set up a shop, and it is adequate for my purposes. In a sort of immersion thinking, I am also using the barn as my living quarters, which keeps me focused on the project.

I picked up a small drill press to aid on this.

My first task is to get the mechanical portion set up. For this, I built a buck to use for placement, adjustment, and refinement.

You can see in the photo (bad as it is) that I have mounted the crank on the front of a ten foo

t post. Then I sat on it and got a rough placement for my seat. With that figured out, I was able to route the shaft so that it would be out of my way.

Getting this all dialed in has been more tricky than I thought, and I have moved the seat around quite a bit- note the large pile of sawdust from the drilling.

I am still having a difficult time finding an appropriate universal joint for the drive shaft, so I made a quick one from some half-inch rubber compressor hose and a couple of clamps.

The other components I have to mess with are going to be as tough. For now I am simulating the gears which will run between the front and rear shafts (input and output). The output shaft will have a free-wheel on the forward end, so I will need to sort out how that all works out. For now it's a couple of pulleys which roughly emulate the size.

A quick explanation of why I would insert a couple of gears and a chain into what could work almost as-is:

The shaft that is currently in place is not on center. By necessity it comes off the crank at an angle (to miss the back wheel of a bicycle) so, while I was able to use a universal to make it parallel to the major axis of the boat, I will still need it to step over. I am using this as an opportunity to increase the speed of the final output. By making use of some decent ratios, I can amplify the RPM of the front shaft.

The free-wheel is about making use of momentum. On a bicycle the weight of the bike and rider rolling forward lends itself as momentum toward moving forward. Unfortunately, boats don't get much use out of it. The friction between the water and the hull (plus drag and so on) are greater than the resistance in the wind. To improve this, I want to experiment with a flywheel placed on the output shaft, and I am going to do this by using a free-wheel. The result, if I am right, will give the prop momentum and help with the pedaling by balancing the propellor's resistance against the momentum of the flywheel.

We shall see.

The last bit of note is that I have found a lathe to use for the building of my prop, so I should have a chance at that next week. For now, I am heading back to the city for a few days and will postpone any further work until Thursday.